Safety lock mechanism



Nov. 5, 1968 SAM SHlAO-MING HSU SAFETY LOCK MECHANISM 4 Sheets-Sheet 1 Filed March 8, 1966 u UJUUU u INVENTOR SAM SHIAO-MING HSU $44. ATTORNEYS Nov. 5, 1968 SAM SHlAO-MING HSU 3,408,341

SAFETY LOCK MECHANISM Filed March 8, 1966 4 Sheets-Sheet 2 INVENTOR SAM SHIAO-MING HSU 5 A'iTORNEYS Nov. 5, 1968 SAM SHIAO-MING Hsu 3,408,84

SAFETY LOCK MECHANISM Filed March 8, 1966 4 Sheets-Sheet 3 INVENTOR SAM SH |AO-MING HSU BY 41%,", JLM &,..',&e

ATTORNEYS Nov. 5, 1968 SAM SHlAO-MING HSU 3,

SAFETY LOCK MECHANISM 4 Sheets-Sheet 4 Filed March 8, 1966 W 6 I F INVENTOR 1 SAM SHlAO-MING HSU 5 g 4M M ATTORNEYS Iii 3,408,841 SAFETY LOCK MECHANISM Sam Shiao-Ming Hsu 147-35 Grand Central Parkway, Jamaica, N.Y. 11435 Filed Mar. 8, 1966, Ser. No. 532,677 Claims. (Cl. 70390) ABSTRACT OF THE DISCLOSURE This invention relates generally to door locks and more particularly to a safety lock mechanism for making locks secure against unauthorized entry.

While locks are ordinarily adequate to prevent entry by one without a key, pass keys are too often available to unauthorized persons.

Accordingly, it is a primary object of the invention to make a lock secure despite the possession of a proper key by an unauthorized person. A further object of the invention is to provide means whereby it becomes apparent that an attempt has been made to effect unauthorized passage.

Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.

Generally speaking, the invention embodies means that can be added to a lock mechanism for accomplishing the desired objectives. A lock constructed in accordance with the invention includes a dial with numbers on its face. The dial is mounted for rotation about the key plug, a preselected setting of the dial being required to permit the lock to be unlocked by its key. When the dial is set at the opening number, the lock may be unlocked or locked in the usual manner by use of the proper key. However, if the dial is set on any other number, and the proper key is inserted into the key plug, the key may be turned only slightly whereupon the door remains locked and the key is trapped in the partially turned portion. The key may be removed only when the dial is manipulated to set the proper release combination. The preselected opening number may be reset, as desired.

In a preferred construction, a tumbler and cylinder lock has an elongated plate secured to the back of the cylinder so that the plate is generally vertical when the tumblers are locking the cylinder. The lower end of the plate is fixed to the cylinder and, in the vertical position, the plate depresses a spring loaded pin. When the plate is turned with the cylinder in the opening direction, the pin springs out and exposes a flat side to the plate, thus preventing the plate from being turned back to the vertical position. It may only return to the vertical by completing a full revolution wherein means operated by the plate effect depression of the pin as the plate approaches the vertical.

d States atent O ice During the initial turning, as the plate approaches a quarter revolution, it meets a second pin which, if the opening number has been set, is depressed by the plate. It the opening number was not set, the second pin cannot be depressed and rotation of the plate is arrested by both pins, thus preventing the key from being withdrawn. When the first pin is biased outwardly, the dial is locked to prevent a further attempted selection of the appropriate opening number.

A rod is mounted above the tumblers and is connected to the first pin in such a way that, as the rod is pulled back, the pin is depressed to permit release of the trapped key.

The invention comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a front elevational view of a lock constructed in accordance with the invention;

FIG. 2 is a partial sectional view taken along line 22 of FIG. 6;

FIG. 3 is a partial perspective view of the pin assembly;

FIG. 3A is a partial sectional view taken along line 3A3A of FIG. 3;

FIG. 4 is a partial sectional view taken along line 4-4 of FIG. 2;

FIG. 5 is a partial perspective view of the preferred trapping mechanism;

FIG. 6 is a sectional view taken along line 66 of FIG. 2, with the parts being shown in the locked position;

FIG. 7 is a view similar to FIG. 6, with the parts being shown in the unlocked position;

FIG. 8 is a sectional view taken along line 8-8 of FIG. 2;

FIG. 9 is a sectional view taken along line 99 of FIG. 2;

FIG. 10 is a rear elevational view of a modified form of trapping mechanism;

FIG. 11 is a partial sectional view taken along line 1111 of FIG. 10; and

FIG. 12 is a partial perspective view of the modified trapping mechanism of FIG. 10.

Referring now to the drawings and especially FIGS. 1 and 2, a lock cylinder 21 is mounted in the usual door 22 and includes a known type of cylinder barrel 23 having a key receiving slot 24. A dial 25 inscribed with indicia 26 is rotatably mounted about cylinder 21 at the front face thereof. A plate 27 may be provided for limiting the outward movement of dial 25. Two idler gears 28 and the gear 29 are rotatably and slidably mounted in the cylinder and cooperate with a ring gear 31 forming a portion of the inner surface of dial 25. Gears 28 and 29 aid in rotatably mounting dial 25 about cylinder 21. Gear 29 is fixed on a shaft 32 rotatably and axially slidably mounted in cylinder 21 with shaft 32 extending through the rear of lock cylinder 21 and being of sufficient length to extend well beyond the inside of the door, as shown in FIG. 2. The opposite end of shaft 32 is provided with a knob 33.

A trapping ring 34 (FIGS. 3 and SA) has a U-shaped cross section with an inner leg 35 riding on the periphery of lock cylinder 21 and an outer leg 36 in engagement with the rear face of the lock cylinder. The outer surface of trapping ring 34 is provided with a plurality of teeth 37 adapted to engage a gear 38 fixed to shaft 32. The gearing is so selected that a single rotation of dial 25 effects a single rotation of trapping ring 34. Clips 39 may be suitably provided to hold trapping ring 34 in the assembled position with respect to the lock cylinder without interfering with the rotation thereof. Inner leg 35 is provided with a slot 41 whose use will be hereafter described.

Referring now to FIGS. 2 through 6, a pin 42 is slidably mounted in lock cylinder 21 and is biased outwardly by means of a spring 43. An inner portion of pin 42 may have a generally rectangular or other suitable cross-section to prevent axial rotation of the pin within the cylinder lock. The pin is provided with a rounded outer end 44 whose use will be hereafter described. Referring especially to FIG. 3A, pin 45 normally is positioned between the legs of trapping ring 34 but, when aligned with slot 41, permits pin 42 to be depressed against the action of spring 43.

As seen in FIG. 6, a plate 46 is mounted for rotation with cylinder barrel 23 and the outer end 47 normally depresses a pin 48, also slidably mounted in cylinder 21 and biased outwardly by a spring 49. The outer portion of pin 48 is provided with a fiat 51 and a rod 52 extends perpendicularly from pin 48. A plurality of teeth 53 extend inwardly toward rod 52 from the periphery of trapping ring 34 with a tooth being provided for each tooth on the trapping ring.

When the proper key is inserted in the cylinder barrel and the barrel is rotated (in the counterclockwise direction as shown in FIG. 6) outer end 47 rotates and releases the holding pressure on pin 48 whereby it is biased outwardly to move rod 52 into engagement with one of teeth 53 to prevent rotation of trapping ring during the opening cycle. If the proper opening indicia has been set, pin 45 is aligned with slot 41 and outer end 47 cams over rounded end 44 to depress pin 42. On the other hand, if the proper opening number has not been set, depression of pin 42 will be prevented by cooperation between rod 45 and the legs of the trapping ring. On such attempted unauthorized entry, the cylinder barrel can not be rotated in the reverse direction to its original position as such is prevented by flat 51 which has been interposed in a blocking position with respect to plate 46 upon the outward movement of pin 48. Thus the lock. is effectively jammed in a partially turned position and the key may thereby not be withdrawn. Likewise, further selection of the proper opening number by rotation of dial 25 is prevented by the engagement of rod 52 between adjacent teeth 53.

On authorized entry, when the proper opening indicia has been set, plate 46 rotates in a counterclockwise direction (FIG. 6) and, as it approaches a full circle, outer end 47 moves toward pin 48 which is in a blocking position. Pin 48 may have a cam shaped outer end permitting end 47 to ride thereover. Pin 48 may also be depressed through use of a plate 54 which is pivoted to lock cylinder 21 and has an upstanding flange 55 which is caused to move into contact with and cam over rounded end 44. Such movement is effected by means of a projection 56 on plate 46 in engagement with flange 55. As plate 54 cams over rounded end 44, pin 42 is caused to retract. A channel 57 (FIG. connected to pin 42 through an arm 58 effects withdrawal of pin 48 in order that plate 46 may take up a position holding pin 48 depressed. When the lock has been opened, plate 54 attains the position shown in FIG. 7, its movement being limited by a stop 59.

On reverse rotation, a projection 60 on outer end 47 likewise carries plate 54 over rounded end 44 to again depress pin 42 and move pin 48 inwardly to Permit plate 46 to return to the rest position.

Turning again to the situation wherein the key has been trapped by advancement of rod 52 between adjacent teeth 53, means are provided for returning the lock to the normal lock position by an authorized person so that the key may be removed. Such means are best described in connection with FIGS. 2, 5, 8 and 9.

As heretofore stated, shaft 32 is slidable within cylinder 21 but is normally fixed when the parts are in the usual position. When pin 48 moves outwardly, a rod 61 extending therefrom slides forwardly in a slot 62 cut in a plate 63 which is secured to shaft 32.

When pin 48 moves outwardly, rod 61 slides forwardly to the limit of slot 62 thereby permitting shaft 32 to move forwardly with dial 25 on depression of the dial. The forward movement of shaft 32 moves gear 38 out of engagement with the teeth on trapping ring 34 to thereby permit free rotation of dial 25 and shaft 32. Note that plate 63 is mounted on shaft 32 by means of a collar 64 which permits relative rotation between the collar and shaft 32 with collars 65 being mounted fast on shaft 32 to prevent relative axial movement between collar 64 and shaft 32. In this free position of shaft 32, rotation of the shaft can be etfected either through dial 25 or knob 33 on the inside of the door.

To the inside of the door is secured a plate 67 having a plurality of blind holes 68 therethrough. A spline 69 extends outwardly from the center of plate 67 and has slideably mounted thereon a plate 71. Collar 72 fast on shaft 32 effects axial movement of plate 71 through clip 70 with the shaft but splines 69 prevent rotational movement of plate 71.

Rotatably mounted about spline 69 are a plurality of fingers 73 each carrying a pin 74 having a head 74A, a projection 75 and a clip 76. Heads 74A are received in depressions 77 in plate 71 so as to provide for indexing of fingers 73 on rotation thereof with clips 76 riding in a groove 79 to urge the heads into the depressions. An arm 78 is rotatably mounted on cover plate 80 and is keyed, through arm 81 for rotation with shaft 32.

The normal position of dial 25 is as shown in FIG. 1 and, as heretofore described, outward movement of pin 61 in slot 62 permits inward movement of dial 25. Outward movement of the dial is normally prevented by engagement of pins 74 with the surface of plate 67. However, if each pin 74 is aligned with a cooperating hole 68, outward movement of dial 25 is possible.

When a key has been jammed due to attempted unauthorized entry, it is necessary to withdraw rod 32 to pull back on pins 42 and 48. An authorized person has knowledge of the location of holes 68 which are spaced about a circle which is keyed with the indicia on the face of dial 25. When the lock is jammed, dial 25 is moved inwardly to free shaft 32 for rotation. The inward movement also moves plate 71 toward arm 78 and, with arm 78 in engagement with a projection 75, rotation of the dial causes an associated finger 73 to be indexed to the proper position. The feel is accomplished through cooperation between head 74A and depressions 77. When a finger 73 has been properly aligned, dial 25 is slightly withdrawn to permit arm 78 to clear the aligned finger and dial 25 is rotated and then moved inwardly so that the next associated finger can be properly aligned. When each of the fingers has been properly aligned to align each pin 74 with an associated hole 68, dial 25 may be pulled out past the normal position whereby the limit of slot 62 through rod 61 effects withdrawal of pin 48 so that plate 46 may be returned to the normal position.

Thus, not only is unauthorized opening of a lock prevented by one having the correct key, but release of the jammed mechanism can only be accomplished by one knowing the correct locations of holes 68. Since fingers 73 are indexed with pins 74 out of contact with plate 67, the proper setting of the fingers can not be accomplished through feel and thus the lock can not be picked even for the purpose of withdrawing the key.

Resetting the correct opening number can be easily accomplished. Dial 25 is set at the correct opening number and cylinder barrel 23 is partially turned. This allows pin 48 to move outwardly to thereby permit depression of dial 25 to move gear 38 out of engagement with the teeth on trapping ring 34. Dial 25 is freely rotated to a newly selected number and the dial is moved axially outwardly to its original, normal position. This has not changed the correct position of trapping ring 34 and thus the lock may be fully opened and the new number is set.

A modified form of-the invention is shown in FIGS. through 12, wherein the second pin, pin 42, may be eliminated. In this embodiment, =pin 48A has a rounded end and is provided with an upstanding rod 52A which performs the locking operation heretofore described. Plate 46A is modified to have an elongated configuration with cam-shaped edges as shown in section in FIG. 11. A central aperture 82 is also formed with cam-shaped walls andteeth 53A are modified to provide a fiat 83 at the position corresponding to the correct opening number. The mechanism is otherwise constructed as heretofore described. With the embodiment shown in FIGS. 10 through 12, rotation of plate 46A will be accomplished by rotation of cylinder barrel 23 with the key. If the correct opening number has been selected, pin 48A will advance only partially into aperture 82, further advance being prevented by cooperation between rod 52A and fiat 83. This prevents pin 48A from becoming jammed in plate 46A and the rounded end of the pin cams over the cam-shaped aperture 82 to permit continued rotation of plate 46A.

On the other hand, if the correct opening number has not been selected, rod 52A engages in the deep cut be tween adjacent teeth 53A thereby advancing pin 48A fully into aperture 82 to lock plate 46A against further movement. The mechanism for releasing the jammed pin would be as heretofore described.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above constructions without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

What is claimed is:

1. A safety lock mechanism in combination with a lock cylinder having a rotatable cylinder barrel comprising a dial rotatable with respect to said lock cylinder and having indicia on the face thereof, a plate mounted for movement with said cylinder barrel, pin means slidable in said lock cylinder and positionable in the path of movement of said plate, said pin means engaging said plate only after said cylinder barrel has been partially rotated from locked positionthereof, trapping means for selectively permitting or preventing blocking engagement between said pin means and said plate, and motion transmitting means interconnecting said dial and said trapping means for moving said trapping means to a position to permit non-blocking engagement between said pin means and said plate when said dial is rotated to a preselected setting of said indicia so that said cylinder barrel can be rotated to an unlocked position.

2. A safety lock mechanism as claimed in claim 1 wherein said trapping means includes a trapping ring rotatable with respect to said lock cylinder and having a plurality of axially extending teeth, said pin means being provided with a rod extending therefrom adapted to engage between said teeth for locking of said trapping ring, said plate being positionable over said pin means to hold said pin means depressed and being movable out of engagement therewith to permit release of said pin means whereby said rod engages between said teeth.

3. A safety lock mechanism as claimed in claim 2 wherein said motion transmitting means includes a rotatable shaft extending between said dial and said trapping ring, said shaft carrying gears in mesh with teeth on surfaces of said dial and trapping ring to effect rotation of said ring through said dial.

4. A safety lock mechanism as claimed in claim 2 wherein said plate is provided with an aperture for fully receiving said pin means when said dial is rotated to other than a preselected setting of said indicia.

5. A safety lock mechanism as claimed in claim 1, wherein said trapping means includes a tapping ring rotatable with respect to said lock cylinder and having a channel-shaped cross-sectional configuration and a slot in one leg thereof, said pin means having a rounded end adapted for engagement by said plate, said pin means having a rod extending therefrom and normally disposed between the legs of said channel-shaped trapping ring, said pin means adapted to be depressed when said rod is disposed opposite said slot in said one leg of said trapping ring, depression being accomplished by the camming action of said plate thereover, depression being prevented by said one leg of said trapping ring when said slot is not in the required preselected position to thereby prevent further movement of said plate.

6. A safety lock mechanism as claimed in claim 5 wherein a second pin is slideable in said lock cylinder and includes a second rod extending from said second pin, said trapping ring being provided with a plurality of circumferentially spaced teeth extending toward said second rod, said second pin being normally depressed by engagement with said plate and being adapted to advance to move said second rod into blocking engagement between a pair of said teeth to thereby prevent rotation of said trapping ring when said plate is out of engagement with said second pin.

7. A safety lock mechanism as claimed in claim 6 and including channel means extending from said pin means and slideably receiving said second pin.

8. A safety lock mechanism as claimed in claim 7 and including a second plate pivoted to said lock cylinder and adapted for depression of said pin means on engagement between said second plate and the outer end of said pin means, said first plate including means for cooperating with said second plate for effecting rotation of said second plate during a preselected portion of the cycle of rotation of said first plate.

9. A safety lock mechanism in combination with a locking device comprising a dial rotatable with respect to said locking device and having indicia on the face thereof, pin means slidable with respect to said locking device and adapted for selectively blocking said locking device for preventing movement of said locking device from a locked position to an unlocked position while permitting limited movement of said locking device from said locked position into an intermediate position wherein further movement of said locking device is prevented, said pin means including means for preventing return movement of said locking device from means intermediate position to said locked position, release means cooperating with said pin means for releasing said locking device so that said locking device can be moved from said intermediate position, trapping means cooperating with said pin means for selectively permitting or preventing blocking of said locking device by said pin means, and motion transmitting means interconnecting said dial and said trapping means for moving said trapping means to permit said pin means to be located in a non-blocking position when said dial is rotated to a preselected setting of said indicia so that said locking device can be moved to said unlocked position.

10.. A safety lock mechanism as claimed in claim 9, and including means for moving said dial with respect to said trapping means comprising a plurality of rotatable fingers each having a finger pin projecting therefrom, means defining a surface for abutment by said finger pins for preventing movement of said dial with respect to said trapping means, and a plurality of bores in said surface defining means for receiving said finger pins on rotation of said fingers to preselected positions whereby to permit advancement of said fingers and said surface defining means toward one another to thereby permit permit unblocking of said locking device.

References Cited UNITED STATES PATENTS Rautbord I 70-284 Carroll 70-284 Carroll 70-284 Machinist 70-284 'Piagneri 70-284 Machinist 70-284 Smith 70-284 MARVIN A. CHAMPION, Primary Examiner.

movement of said dial relative to said trapping means to 15 TEITELBAUM, Assistant Exa iner- 

